The detection of ovarian cancer is at the present time extremely difficult, resulting in the identification of disease only when it has substantially progressed. For this reason, it is essential to find a diagnostic approach for early identification of progressive disease. The investigators propose an innovative approach to identify autologous reactions of ovarian cancer patients to tumor-associated antigens, which they will use to develop a test of developing immunity to these antigens. The approach is based on several technical developments integrated into a single analytical scheme. They include an ultrasensitive assay system which is based on the coagulation cascade and adaptable to solid phase-associated proteins, a method for isolation of membrane-associated antibodies from "membrane fragments" present in the ascites fluids of ovarian cancer patients, a system for the selective isolation of reactive haptene-labeled antibodies by absorption-elution from anti-haptene absorbent, and the availability of cultured cells and specific antigens already found to be reactive with antibodies from ovarian cancer patients' sera. The approach to be used is to isolate the antibodies, label them with various haptenes, bind them to specific biotinylated proteins and fractionate them onto anti-haptene absorbent in order to selectively isolate antibodies with specific reactivities. In addition, the investigators will develop specific assays for human antibodies to procathepsin D and to glucose-regulated protein 78 which should be usable in undiluted serum and able to detect very low concentrations of these specific antibodies. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE